ML19343B302

Application for Amend to CPPR-108 & CPPR-109 to Reflect Mod in Plant Design.Mod Would Substitute More Restrictive Primary Leakage Containment for Encl Bldg.Class I & III Fees & Cost/Benefit Assessment Encl

ML19343B302
Person / Time
Site:	Vogtle
Issue date:	12/19/1980
From:	Ehrensperger W GEORGIA POWER CO.
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
NUDOCS 8012230197
Download: ML19343B302 (5)

Text

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5 Director of Nuclear Reactor Regulation 0 s

-E Attn: Darrell C. Eisenhut, Director Division of Project Management U.S. Nuclear Regulatory Commission Washington, D.C. 20555 NRC DOCKET NUMBERS 50-424 AND 50-425 CONSTRUCTION PERMIT NUMBERS CPPR-108 AND CPPR-109 ALVIN W. V0GTLE NUCLEAR PLANT-UNITS 1 AND 2 APPLICATION FOR AMENDMENT

Dear Mr. Eisenhut:

Georgia Power Company (GPC) acting on its own behalf and agent for Oglethorpe Electric Membership Corporation, Municipal Electric Authority Of Georgia, and the City Of Dalton by this application requests amendment of CPPR-108 and CPPR-109, Construction Permits for the Alvin W. Vogtle Nuclear Plant, Units 1 and 2, to reflect a modification in plant design.

The modification would substitute for a structure and associated systems described genernlly as'an enclosure building in the application for Vogtle licenses, a more restrictive primary containment leakage commit-ment which, together with onsite meteorological data, ensures more reliably attained offsite post-accident doses which are less than, or comparable to, doses judged to be acceptable for design now and at the time construction was initially authorized.

In support of this application for amendment, Georgia Power Company relies on information submitted in Supplement 6, dated August 12,1979, to its application for Construction Permit and Operating License, which included a description of the associated physical modifications. These modifications would entail removal of the upper portion of the enclosure building and its related equipment described in Sections 1. 2.6, 3.8.4.1.1, and 6.6 of the Vogtle PSAR, while retaining from grade to the 270-foot level an equipment building described in Sections 1.2.6 and 3.8.4.1.1 of Supplement 6.

In further support of this request for amendment, Georgia Power Company will submit under a separate cover on December 30, 1980, Supplement 8 to the application, additional information on the more restrictive primary containment leak rate and the resultant projected offsite. doses for a design basis accident if the requested modifications are authorized.

As was discussed at a meeting with the NRC on December 1,1980, Georgia Power Company, as a part of this amendment request, is prepared to commit to a containment leak rate of 0.2 weight percent per day if the - .

enclosure building is modified. Employing this leakage rate, and dispersion factors derived using NRC methocology and the latest onsite meteorological

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Mr. Darrell C. Eisenhut Page 2 data, Georgia Power Company has calculated the following design basis accident offsite doses for the Vogtle units, as modified.

Exclusion Area Boundary Thyroid (Rem) 111 Whole Body (Rem) 3 Low Population Zone Thyroid (Rem) 73 Whole Body (Rem) 1 These doses, calculated without taking any credit for leakage filtration even though the majority of the containment penetrations are included within a safety-related negative pressure and filtration boundary, are comparable to, or less than, the projected doses calculated and determined acceptable now and at the time the Vogtle construction was authorized. These dose projections, moreover, would be achieved under the requested modification by increased reliance on the passive primary containment and more restric-tive technical specification requirements rather than the passive / active system comprised of an enclosure building and filtration equipment.

Approval of the requested modification will result in reduced incre-mental environmental impact due to construction and operation. An assessment of the minimal incidental environmental costs and benefits is included as Attachment 1 to this amendment request.

In view of the potential impact on actual construction progress which could result from the NRC's action on the amendment request, and recognizing the limited technical issues presented by the request, we request consideration of our application by January 30, 1981. Three(3) signed originals and forty (40) copies of the application are provided for your use.

The class of this proposed amendment is designated according to 10 CFR 170 requirements. Since this change is deemed not to involve a -

significant hazard consideration and does involve a single issue.it is considered a Class III change for Unit 1 and a Class I change for Unit 2.

A check for $4,400 is enclosed to cover the fees involved.

l fW. E. Ehrenspepjer CAJA4C h

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Senior Vice Pfesident Power Supply Georgia Power Company Sworn to and subscribed before me this /f day of December,1980.

Y // Y Notary Public sum My Commission Loires Sept. 20,1983

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! Page 1 of 3 ATTACHMENT 1 COST / BENEFIT ASSESSMENT (1) Description of Change:

The proposed design utilizes the existing steel-lined, prestressed, post-tensioned concrete containment building and a revised commitment to i 0.2% per day post-accident leak rate, and assumes no credit for filtration of leakage which enters the penetration area's filter boundary where a j majority of containment penetrations are located. This proposed design modifies the original plant design by not implementing the upper portion of the enclosure building while retaining the lower structure as the equipment building, and deleting the associated filtration system.  !

This cost / benefit assessment is based upon:  !

Original Design Proposed Design o Prestressed, post-tensioned o No change concrete containment building o Enclosure building o Equipment building (lower portion of original enclosure building) l o 0.3% per day primary contain- o 0.2% per day primary contain-ment leak rate ment leak rate o Two-minute enclosure build- o Not applicable (no credit ing drawdown time taken for existing penetration

filtration boundary) i (2) Construction Impacts

The proposed design will result in savings in construction man-hours and resource commitments. The original plant design requires a commitment of the following resources that would not be required in the proposed design:

o Construction 350,000 manhours o Engineering No impact i

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1 Attachment 1 Page 2 of 3 Cost / Benefit Assessment Resource Commitment -

4 o Structural steel 4,000 tons 2

o Metal siding 200,000 ft o Embeds 120 tons o Ducting 600,000 lbs.

o Conduit 7,000 feet o Cabling 11,200 feet (3) Operational Impacts:

The enclosure building filtration system filters would require periodic testing for filtration capability and leakage, and would require periodic maintenance and possible repair during the life of the plant. Operation and maintenance of the original design would require periodic leak testing of the structure, with consequent building sealing efforts required if sealant deterioration prevents the enclosure building filtra-tion system from attaining a negative 0.25 in. H20 pressure within 2 minutes of initiation. Both features increase the probability of a potential Technical Specification conflict during plant operation that may result in unscheduled outages. These efforts and potential negative impacts are avoided with the proposed design.

l Both the original and proposed plant designs require maintaining specified primary containment leak rates (i.e., 0.3% per day and 0.2% per day, respectively) . Achieving these leak rates requires similar maintenance operations, with a greater effort needed to achieve 0.2% per day.

The proposed design results in generally comparable or lower post-accident doses than are attained with the original design.

Modification of the enclosure building has no impact on doses during normal operation and does not change the plant vent release point. The original enclosure building filtration system was not designed to operate during normal operation, and thus no credit would be taken for any dose reduction afforded by continuous or intermittent operation of this filtra-tion system. The plant vent location and height does not change by modifying the enclosure building.

No significant environmental impacts such as heat rejection to the en-vironment or increase in station water use results by modifying the enclosure building. Heat generated from the operation of enclosure building filtration system equipment would be small, and modifying the enclosure building deletes this equipment from the design.

The external appearance of the station will be enhanced by modifying the enclosure building as it will provide a smaller profile and improves the integration of the facility into the environmental setting. The original

Attachment 1 Page 3 of 3 Cost / Benefit Assessment enclosure building would appear as a large box-like structure nearly 190 feet high and 175 feet wide. The modified building design appears as a cylindrical concrete shell with a smooth hemispherical concrete dome approximately 180 feet high and 150 feet wide.

The operational impact on the air and water quality, due to the effluents, in the vicinity of the plant site was judged to be insignificant for the original design,and implementation of the proposed design will not affect these effluents at all .